Unfortunately dojos are filled with human beings with human failings. When those failings include ego injuries occure. everyone in the dojo is responsible for the safety and mentoring of the junior members. The most junior member is responsible to learn from the senior members and protect him/her self to be able to advance without injury.
Speaking of injury. If your shoulder is hurt that much PLEASE don't use that side in a technic untill you are properly healed. There is NEVER a good reason to risk long term injury. When I injured my elbow I merely kept the technics to the other arm until I was healed. neither my partners or my sensei minded. In fact they were happy to see that I wouldn't put them in a position where it would make them feel bad if they injured me further. BTW the elbow injury I sustained wasn't injured in the dojo.